fix(gemini): 移除空返图占位并暴露失败原因

Gemini 图片响应未包含可提取资源时，不再返回伪造占位图，改为非重试失败并保留安全拦截、候选结束状态和上游错误等结构化诊断。\n\n同步将诊断写入 HTTP 错误、任务结果、attempt 指标和日志，确保任务失败时不结算，并补充单元及 PostgreSQL 验收测试。\n\n验证：gofmt、go test ./... -count=1、go vet ./...、迁移安全检查、pnpm openapi。
2026-07-29 19:50:43 +08:00
parent 012823adff
commit 3886048e0f
9 changed files with 506 additions and 8 deletions
@@ -1533,6 +1533,94 @@ func TestGeminiClientImageGenerateBuildsNativeImageBody(t *testing.T) {
 	}
 }

+func TestGeminiClientImageGenerateRejectsPromptBlockedWithoutImage(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		w.Header().Set("X-Request-Id", "gemini-blocked-request")
+		_ = json.NewEncoder(w).Encode(map[string]any{
+			"promptFeedback": map[string]any{
+				"blockReason":        "SAFETY",
+				"blockReasonMessage": "The request was blocked by the image safety policy.",
+			},
+			"usageMetadata": map[string]any{"promptTokenCount": 12, "totalTokenCount": 12},
+		})
+	}))
+	defer server.Close()
+
+	_, err := (GeminiClient{HTTPClient: server.Client()}).Run(context.Background(), Request{
+		Kind:      "images.generations",
+		ModelType: "image_generate",
+		Model:     "gemini-image",
+		Body:      map[string]any{"model": "gemini-image", "prompt": "blocked prompt"},
+		Candidate: store.RuntimeModelCandidate{
+			BaseURL:           server.URL,
+			ProviderModelName: "gemini-image",
+			ModelType:         "image_generate",
+			Credentials:       map[string]any{"apiKey": "gemini-key"},
+		},
+	})
+	if err == nil {
+		t.Fatal("missing Gemini image must fail instead of returning a placeholder")
+	}
+	if ErrorCode(err) != "gemini_image_output_missing" || IsRetryable(err) {
+		t.Fatalf("unexpected missing image error: code=%q retryable=%v err=%v", ErrorCode(err), IsRetryable(err), err)
+	}
+	meta := ErrorResponseMetadata(err)
+	if meta.RequestID != "gemini-blocked-request" || meta.ResponseDurationMS < 0 {
+		t.Fatalf("missing image error lost response metadata: %+v", meta)
+	}
+	details := ErrorDetails(err)
+	if details["reason"] != "prompt_blocked" || details["promptBlockReason"] != "SAFETY" || details["candidateCount"] != 0 {
+		t.Fatalf("unexpected prompt block details: %+v", details)
+	}
+	if !strings.Contains(err.Error(), "blockReason=SAFETY") || strings.Contains(err.Error(), "gemini-image-placeholder") {
+		t.Fatalf("missing image error should explain the upstream block without a placeholder: %v", err)
+	}
+}
+
+func TestGeminiMissingImageDetailsExplainEmptyImagePayload(t *testing.T) {
+	details := geminiMissingImageDetails(map[string]any{
+		"candidates": []any{map[string]any{
+			"finishReason": "STOP",
+			"content": map[string]any{"parts": []any{
+				map[string]any{"inlineData": map[string]any{"mimeType": "image/png", "data": ""}},
+				map[string]any{"text": "The model completed without producing an image."},
+			}},
+		}},
+	})
+	message := geminiMissingImageMessage(details)
+
+	if details["reason"] != "empty_image_payload" || details["candidateCount"] != 1 || details["partCount"] != 2 {
+		t.Fatalf("unexpected empty image payload details: %+v", details)
+	}
+	if !strings.Contains(message, "missing inline data or file URI") ||
+		!strings.Contains(message, "finishReason=STOP") ||
+		!strings.Contains(message, "The model completed without producing an image.") {
+		t.Fatalf("missing image message should preserve the concrete extraction reason: %s", message)
+	}
+}
+
+func TestGeminiMissingImageDetailsPreserveUpstreamErrorEnvelope(t *testing.T) {
+	details := geminiMissingImageDetails(map[string]any{
+		"error": map[string]any{
+			"code":    500,
+			"status":  "INTERNAL",
+			"message": "image backend returned no generated asset",
+		},
+	})
+	message := geminiMissingImageMessage(details)
+
+	if details["reason"] != "upstream_error" ||
+		details["upstreamErrorCode"] != "500" ||
+		details["upstreamErrorStatus"] != "INTERNAL" {
+		t.Fatalf("unexpected upstream error details: %+v", details)
+	}
+	if !strings.Contains(message, "upstreamErrorCode=500") ||
+		!strings.Contains(message, "upstreamErrorStatus=INTERNAL") ||
+		!strings.Contains(message, "image backend returned no generated asset") {
+		t.Fatalf("upstream error message should remain diagnostic: %s", message)
+	}
+}
+
 func TestGeminiGenerationConfigInitializesMissingImageConfig(t *testing.T) {
 	config := geminiGenerationConfig(map[string]any{
 		"aspect_ratio": "16:9",